1. Field of the Invention
This invention relates to discharge collectors for pumps and more particularly to a discharge collector for a rotary pump of a pool-type nuclear reactor.
2. Description of the Prior Art
Nuclear power facilities for the generation of electrical power include a sealed containment vessel in which is located the reactor core. In a loop reactor only the reactor core and portions of the core assembly transfer mechanism are located within the vessel. The pumps and heat exchangers are located externally of the vessel. Therefore, the size and geometry of the pumps are not critical. However, in a pool-type nuclear reactor in addition to the nuclear reactor core, various auxiliary equipment, such as intermediate heat exchangers, pumps and the like, are all immersed in a pool of liquid metal coolant within the containment vessel. The pump envelope is basically determined by the outer diameter of the collector. Therefore, since the envelope diameter of the components within the containment vessel establish the containment vessel diameter, the pump collector size is a contributing element. Conventional discharge collectors such as the 4-tongue, 4-discharge volute distributes the flow radially with the four outward spiraling volute passages nested to each other. The spiral configuration of the collector (volute) creates a large envelope diameter. Multiple volute tongues (and corresponding discharges) help reduce the envelope diameter.
In the device disclosed in U.S. Pat. No. 3,910,714 entitled, "Liquid Metal Pump for Nuclear Reactors" issued to H. G. Allen et al, fluid leaves the impeller of the rotary pump and is directed through diffuser passages which turn the tangential (i.e. circumferential) flow to a radial flow. The fluid then flows through straightening vanes which direct the flow radially inward and through a discharge adapter in an axial direction. The relatively long length and number of turns in the fluid path of the device reduces the efficiency.